Lift truck with laterally tiltable lifting unit



1". P. SIMOVICH 3,482,722

LIFT TRUCK WITH LATERALLY TILTABLE LIFTING UNIT Dec. 9, 1969 2Sheets-Sheet 1 Filed Jan. 19, 1968 Dec. 9, 1969 r. P. SIMOVICH 3,482,722

LIFT TRUCK WITH LATERALLY TILTABLE LIFTING UNIT Filed Jan. 19, 1968 2Sheets-Sheet 2 mas/779E.

jw/ J- S/MOVICAG 77 64s 47922?! United States Patent 3,482,722 LIFTTRUCK WITH LATERALLY TILTABLE LIFTING UNIT Tom P. Simovich, 74 MagnaVista, Arcadia, Calif. 91006 Filed Jan. 19, 1968, Ser. No. 699,092 Int.Cl. B66f 9/16 US. Cl. 214701 3 Claims ABSTRACT OF THE DISCLOSURE A lifttruck having a lifting unit which is both laterally tiltable andlaterally shiftable. The lifting unit includes a supporting structureconnected to the elevating means on the mast of the lift truck.Forwardly of the supporting structure is a laterally tiltable structurewhich is rendered laterally tiltable by means of rollers thereon inengagement with laterally spaced, arcuate tracks on the supportingstructure, such arcuate tracks facing laterally outwardly relative tothe forwardly-extending axis thereof. The arcuate tracks are V-shaped incross section and the rollers have circumferential V-grooves whichreceive the V-shaped tracks to restrain the laterally tiltable structureagainst forward and rearward movement relative to the supportingstructure. A laterally shiftable lifting structure is carried by thelaterally tiltable structure.

BACKGROUND OF THE INVENTION Industrial lift trucks are commonly providedwith lifting units having lifting structures, such as forks, which arelaterally shiftable in a horizontal direction, laterally tiltable in avertical plane and/or laterally swingable in a horizontal plane.Shifting the lifting structure laterally and swinging it laterally aremaneuvers which are useful to compensate for minor misalignments of thelift truck and a load to be picked up, or a location on which a load isto be deposited. Consequently, maneuvering of the lift truck to obtainprecise alignment is not necessary. Making the lifting structurelaterally tiltable provides a way of compensating for any differencebetween the lateral slopes of the surface on which the lift truck ispositioned and the surface on which a load is to be placed, or fromwhich a load is to be removed. For example, sometimes the ground orpavement in front of a load location slopes laterally relative to theload location itself. Being able to tilt the lifting structure laterallyabout a generally horizontal, forwardly extending axis provides a way ofcompensating for such a lateral slope differential.

As further background, the invention contemplates a lifting unit, for alift truck having a mast and having elevating means movable upwardly anddownwardly along the mast, comprising: a supporting structureconnectible to the elevating means of the lift truck; a tiltablestructure pivotally mounted on the supporting structure for lateraltilting movement about a forwardly extending axis; actuating meansinterconnecting the tiltable structure and the supporting structure fortilting the tiltable structure laterally about such axis; a liftingstructure mounted on the tiltable structure for lateral shiftingmovement of the lifting structure relative to the tiltable sructure; andanother actuating means interconnecting the lifting structure and thetiltable structure for laterally shifting the lifting structure relativeto the tiltable structure.

One prior lifting unit of the foregoing type with which I am familiarutilizes a simple pivot between the tiltable structure and thesupporting structure, to permit lateral tilting of the tiltablestructure, together with thrust rollers for offsetting the downwardbending moment produced by a load on the lifting structure.

OBJECTS OF INVENTION A primary object of the invention is to provide apivotal connection, between the laterally tiltable structure and thesupporting structure, comprising: an arcuate track means on one of thesestructures which is symmetrical about the desired forwardly extendingaxis and which faces laterally outwardly away from such axis; rollers onthe other of the structures in engagement with the track means toprovide for lateral tilting of the tiltable structure about theforwardly extending axis; and cooperating means on the track means andthe rollers for restraining the tiltable structure against forward andrearward movement relative to the supporting structure.

Another object is to locate the arcuate track means on the supportingstructure and the rollers in engagement therewith on the tiltablestructure.

A further object of the invention is to provide a track means comprisingtwo arcuate tracks spaced apart laterally of the forwardly extendingaxis mentioned and each engaged by two of the rollers.

An additional object is to provide a construction wherein the tracks aretapered in cross section and wherein the rollers have circumferentialtapered grooves receiving the tracks therein, such rollers and trackscooperating to restrain the tiltable structure against forward andrearward movement relative to the supporting structure, and serving tooppose the downward bending moment resulting from a load on the liftingstructure carried by the tiltable structure.

Still another object is to provide a lifting unit wherein one of thetracks carries a stop which is positioned midway between the ends ofsuch track and which is selectively engageable by the correspondingrollers so as to limit lateral tilting movement of the tiltablestructure about its forwardly extending axis.

An important advantage of a lifting unit conforming to the foregoingobjects of the invention is that the weight of any load carried by thelifting structure is divided between at least two of the rollers on thetiltable structure in engagement with the tracks on the supportingstructure, instead of being supported entirely by a single pivot, thereby avoiding concentrating the stress due to the entire load at onepoint.

The foregoing objects and features of the present invention, togetherwith various other objects and features which will be evident to thoseskilled in the lift truck art in the light of this disclosure, may beachieved with the exemplary embodiment of the invention illustrated inthe accompanying drawings and described in detail hereinafter.

DESCRIPTION OF DRAWINGS In the drawings:

FIG. 1 is a perspective vew of a lift truck equipped with a lifting unitwhich embodies the invention;

FIG. 2 is an enlarged, front elevational view of the lifting unit, andshowing also fragments of the mast and elevating means of the lifttruck;

FIG. 3 is a fragmentary view taken as indicated by the arrowed line 33of FIG. 2, with actuating means for a laterally tiltable structure and alaterally shiftable lifting structure of the lifting unit omitted forclarity;

FIG. 4 is a fragmentary sectional view taken as indicated by the arrowedline 4-4 of FIG. 2;

FIG. 5 is an exploded perspective view illustrating the supporting,tiltable and lifting structures of the lifting unit of the invention;and

FIG. 6 is a semidiagrammatic front elevational view of the lift truckillustrating the lateral tilting movement of the tiltable structurerelative to the supporting structure, the lifting structure beingomitted for clarity.

3 DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF INVENTION Illustratedgenerally in FIG. 1 of the drawings is a conventional lift truckprovided with a mast 12 at its forward end. Movable upwardly anddownwardly along the mast 12 is an elevating means 14 of any suitabletype for raising and lowering a lifting unit of the invention.

The elevating means 14 per se forms no part of the present invention andmay be of any suitable construc tion. Briefly, the particular elevatingmeans 14 shown includes an elevating frame 22 movable upwardly anddownwardly relative to the mast 12 on rollers 24. A hydraulic cylinder26 interconnecting the elevating frame 22 and the mast 12 produces theupward and downward movement of the elevating frame. The lifting unit 20is equipped with rollers 28 which permit the lifting unit to moveupwardly and downwardly relative to the elevating frame. A chain 30 isconnected at one end to the lifting unit 20 and is trained over asprocket at the top of the elevating frame 22, the other end of thechain being anchored relative to the mast 12. Thus, as the hydrauliccylinder 26 extends the elevating frame 22 upwardly, the chain 30 movesthe lifting unit 20 upwardly relative to the elevating frame. However,as previously indicated, the

lifting unit 20 of the invention may be employed with any desired typeof elevating means.

Considering the lifting unit 20 generally, it includes a supportingstructure 34 connectible to the elevating means 14 of the lift truck 10and provided with an arcuate track means 36 which is symmetrical aboutan axis 38, FIG. 6, extending forwardly from the lift truck and whichfaces laterally or radially outwardly away from such axis. Forwardly ofthe supporting structure 34 is a structure 40 which is tiltablelaterally, i.e., which is tiltable in a generally vertical plane, aboutthe forwardly extending axis 38. More particularly, the laterallytiltable structure 40 is provided with rollers 42, preferably four innumber, which engage the track means 36 to permit the structure 40 totilt laterally relative to the supporting structure 34. As will bedescribed hereinafter, the track means 36 and the rollers 42 havecooperating means for restraining the tiltable structure 40 againstforward and rearward movement relative to the supporting structure 34and for resisting the downward bending moment produced by a load on thelifting unit 20. An actuating means 44 interconnects the tiltablestructure 40 and the supporting structure 34 and serves to tilt thestructure 40 laterally about the forwardly extending axis 38. Forwardlyof and carried by the tiltable structure 40 is a laterally shiftablelifting structure 46, the latter being shifted laterally, along agenerally horizontal path, by an actuating means 48 interconnecting thetiltable and lifting structures.

Considering the foregoing basic components of the lifting unit 20 inmore detail, the supporting structure 34 comprises simply a heavy platewhich is oriented generally vertically and which is provided on its rearside with rearwardly extending flanges 52 carrying the rollers 28. Theplate is provided with laterally horizontally spaced arcuate edgesrespectively forming arcuate tracks 54 which constitute the arcuatetrack means 36. The arcuate tracks 54 face laterally outwardly from theforwardly extending axis 38, and are tapered in cross section, as bestshown in FIG. 4.

The tiltable structure 40 is shown as comprising a rec tangular frame onwhich the four rollers 42 are mounted in laterally spaced pairs, therollers of the respective pairs engaging the respective tracks 54. Asshown in FIG. 4, each roller 42 is provided with a circumferentialtapered groove 56 complementary to the corresponding track 54. Thus, theflanges on the rollers 42 and the arcuate tracks 54 cooperate to resistforward and rearward movement of the tiltable structure 40 relative tothe supporting structure 34, and to resist the downward bending momentcreated by a load on the lifting structure 46.

With the foregoing construction, the structure 40 can tilt laterallyrelative to the supporting structure 34 about the forwardly extendingaxis 38, as clearly shown in FIG. 6 of the drawings. Tilting of thestructure 40 is limited by a stop 58 mounted on the plate 50 of thesupporting structure 34 midway between the ends of one of the arcuatetracks 54. The laterally outer end of the stop 58 projects into thepaths of the corresponding rollers 42 and is selectively engageable bysuch rollers to limit tilting of the structure 40 in both the clockwiseand counterclockwise directions. The rollers 42 may be provided withsuitable thrust bearings, not shown, resisting the axial loads imposedthereon.

The actuating means 44 for tilting the structure 40 comprises simply ahydraulic cylinder 60 pivotally connected at its ends to brackets 62 and64 respectively mounted on the plate 50 of the supporting structure 34and on the tiltable structure 40.

As will be apparent, the foregoing construction provides a. very simpleway of making the structure 46 tiltable relative to the supportingstructure 34, only simple parts being required which can be manufacturedrelatively inexpensively. Further, it will be noted that the weighttransferred from the tiltable structure 40 to the supporting structure34 is divided bet-ween two of the rollers 42, instead of beingconcentrated on a single pivot, and that the downward bending moment dueto the load is divided among all four of the rollers 42, thereby furtheravoiding stress concentrations.

Turning now to the lifting structure 46, it is shown as including arectangular frame having adjacent the top thereof a transverselyextending shaft 72 to which L-shaped tines 74 are pivotally connected.The tines 74 have forwardly extending portions 76 which are capable ofsupporting a load, such as a palletized load, and the downward bendingmoment resulting from the load is resisted by engagement of uprightportions 78 of the tines with the front side of the frame 70. Also, thetines 74 may be shifted laterally along the shaft 72 to vary the spacingtherebetween to accommodate a particular load.

The lifting structure 46 is connected to the tiltable structure 40 bymeans of transverse shafts 80 carried by the tiltable structure 40 andrearwardly extending blocks 82 carried by the lifting structure frame 70and slidable on the respective shafts 80. The downward bending momentproduced by a load on the forwardly extending portions 76 of the tines74 is resisted by horizontal rollers 84 on the tiltable structure 40 inengagement with the rear surface of a transverse member 86 of the frame70.

The blocks 82 are laterally slidable on the shafts 80, and the rollers84 are in rolling engagement with the frame member 86, to permit lateralshifting of the lifting structure 46 relative to the tiltable structure40. The actuating means 48 for producing such lateral shifting comprisessimply a hydraulic cylinder 90 pivotally connected at one end to abracket 92 on the tiltable structure 40 and at its other end to abracket 94 on the liftingstructure frame 70.

It will be understood that the various hydraulic cylinders hereinbeforedescribed are powered by hydraulic fluid supplied by a suitable pump,not shown, on the lift truck 10.

Although an exemplary embodiment of the invention has been disclosedherein for purposes of illustration, it will be understood that variouschanges, modifications and substitutions may be incorporated in suchembodiment without departing from the spirit of the invention.

I claim as my invention:

1. In a lifting unit for a lift truck having a mast and having elevatingmeans movable upwardly and downwardly along the mast, the combinationof:

(a) a supporting plate having front and rear sides and having laterallyspaced, upright, tapered arcuate edges symmetrical about a fore-and-afttilt axis;

(b) means on said rear side of said supporting plate 5 for mounting iton the elevating means of the lift truck;

(0) a laterally extending, tiltable, rectangular frame on said frontside of said supporting plate;

(d) four rollers mounted on said tiltable frame equal distances fromsaid tilt axis in a rectangular pattern and rotatable about axesparallel to said tilt axis;

(e) there being two of said rollers adjacent each end of said tiltableframe in vertically spaced relation;

(f) said rollers having tapered circumferential grooves complementary tosaid tapered arcuate edges;

(g) the two rollers adjacent one end of said tiltable frame engaging oneof said tapered arcuate edges and the two rollers adjacent the other endof said tiltable frame engaging the other of said tapered arcuate edges,whereby said tiltable frame may pivot about said tilt axis as saidrollers roll along said tapered arcuate edges, and whereby said rollersand said tapered arcuate edges cooperate to prevent downward and forwardtipping of said tiltable frame relative to said supporting plate;

(h) actuating means interconnecting said supporting plate and saidtiltable frame for pivoting said tiltable frame about said tilt axis;and

(i) lifting means carried by said tiltable frame.

2. A lifting unit as defined in claim 1 wherein said lifting meansincludes:

(a) a laterally extending, rectangular lifting frame on the front sideof said tiltable frame;

(b) transverse shaft means on said tiltable frame adjacent the upperedge thereof;

(c) bearing means on said lifting frame and slidable laterally alongsaid shaft means to permit lateral shifting of said lifting frame;

(d) thrust rollers carried by said tiltable frame adjacent the loweredge thereof and rotatable about upright axes and engageable by thelower portion of said lifting frame to prevent downward and forwardtipping of said lifting frame; and

(e) actuating means interconnecting said lifting and tiltable frames forshifting said lifting frame laterally relative to said tiltable frame.

3. A lifting unit according to claim 2 including:

(a) transverse rod means on said lifting frame adjacent the upper edgethereof; and

(b) L-shaped tines having upright portions the upper ends of which arepivotable on and slidable laterally along said rod means, which bearintermediate their ends against the front side of said lifting frameadjacent the lower edge thereof, and which terminate at their lower endsin forwardly extending portions.

References Cited UNITED STATES PATENTS 1,878,994 9/1932 Abbe.

2,287,469 6/ 1942 Cochran.

2,468,326 4/1949 Gleason.

2,522,128 9/ 1950 Lehmann.

2,752,055 6/ 1956 Hoppert 2l4-652 2,940,068 6/1960 Stiefel.

3,002,639 10/1961 Cavanagh 214-701 X 3,143,233 8/1964 Evans et al.214-652 3,148,793 9/1964 Walter 214-715 X 3,289,873 12/1966 Hansen2l4730 GERALD M. FORLENZA, Primary Examiner RAYMOND B. JOHNSON,Assistant Examiner US. Cl. X.R. 214 -730

